Susceptibility of Iα- and Iβ-Dominated Cellulose to TEMPO-Mediated Oxidation

The susceptibility of I-alpha- and I-beta-dominated cellulose to TEMPO mediated oxidation was studied, in this work since the cellulose I-alpha-allomorph is generally considered to be thermodynamically less stable and therefore more reactive than the,cellulose IF allomorph, Highly crystalline Cladophora, nanocellulcse, which is dominated by the I-alpha-allomorph, was oxidized to various degrees with TEMPO oxidant via bulk electrolysis in the absence of co-oxidants. Further, the Cladophora nanocellulose was thermally annealed in glycerol to produce its I-beta-dominated form and then oxidized. The produced materials were subsequently studied using FTIR, CP/MAS C-13 NMR, XRD, and SEM. The solid-state analyses confirmed that the annealed Cladophora, cellulose was successfully transformed from an I-alpha- to an I-beta-dominated form. The results of the analyses of pristine and annealed TEMPO,oxidized samples suggest that I-alpha- and I-beta-dominated cellulose do not differ in susceptibility to TEMPO-oxidation. This work hence suggests that cellulose from different sources are not expected to differ in susceptibility to the oxidation due. to differences in allomorph composition.